Scatter3d plot

The scatter3d plot creates a three-dimensional scatter plot of the data.

import plopp as pp
import scipp as sc
import numpy as np

Scatter plot using a positions vector

The easiest way to generate a scatter plot is to use a coordinate of the data array that contains data of the vector3 dtype.

We first generate some fake data, meant to represent clusters of points in a three-dimensional space.

nclusters = 100
npercluster = 1000

position = np.zeros((nclusters, npercluster, 3))
values = np.zeros((nclusters, npercluster))

for n in range(nclusters):
    center = 500.0 * (np.random.random(3) - 0.5)
    r = 20.0 * np.random.normal(size=[npercluster, 3])
    position[n, :] = r + center
    values[n, :] = np.linalg.norm(r, axis=1) + n

da = sc.DataArray(
    data=sc.array(dims=['row'], values=values.flatten(), unit='K'),
    coords={
        'position': sc.vectors(
            dims=['row'], unit='m', values=position.reshape(nclusters * npercluster, 3)
        )
    },
)
da

scipp.DataArray (3.05 MB)

• Dimensions:
  • row: 100000
• Coordinates: (1)
  • position
    (row)
    vector3
    m
    [-90.31366594 154.37296297 33.13930362], [-101.50471858 189.40926838 94.8950967 ], ..., [ 218.22247921 24.17628486 -124.02177351], [ 230.05281747 21.54084451 -140.61324214]

    Values:
    array([[ -90.31366594,  154.37296297,   33.13930362],
           [-101.50471858,  189.40926838,   94.8950967 ],
           [ -97.63252558,  175.06410895,   62.04788451],
           ...,
           [ 209.51981381,   12.39707713, -150.32393598],
           [ 218.22247921,   24.17628486, -124.02177351],
           [ 230.05281747,   21.54084451, -140.61324214]])

• Data: (1)
  • (row)
    float64
    K
    53.202, 33.536, ..., 108.106, 111.782

    Values:
    array([ 53.20207685,  33.53642034,  28.80972436, ..., 127.14155103,
           108.10555558, 111.7822277 ])

We then simply specify the name of the coordinate that contains the vector positions using the pos argument:

pp.scatter3d(da, pos='position', color='black', size=2)

Scatter plot with colorbar

To make a scatter plot with a colorbar mapping data values to colors, use cbar=True.

pp.scatter3d(da, pos='position', cbar=True, size=2)

Scatter plot using individual coordinates

It is also possible to create scatter plots using three individual coordinate names for the x, y, z dimensions:

time = np.linspace(0, 10, 50)
x = np.cos(time)
y = np.sin(time)

da = sc.DataArray(
    data=sc.array(dims=['row'], values=time),
    coords={
        'x': sc.array(dims=['row'], unit='m', values=x),
        'y': sc.array(dims=['row'], unit='m', values=y),
        'time': sc.array(dims=['row'], unit='s', values=time),
    },
)

pp.scatter3d(da, x='x', y='y', z='time', size=0.2, cbar=True)